[unreadable] In the United States, more than 250,000 persons annually experience out-of-hospital sudden cardiac death (SCD). However, few, approximately 4%, are revived with standard CPR and advanced life support interventions and survive to be discharged from the hospital. Successful restoration of cardiac function after SCD is dependent on early electrical defibrillation in patients found to be in ventricular fibrillation (VF) and early provision of effective artificial circulation and ventilation, i.e., CPR. However, standard CPR, as currently practiced, provides only 10-20% of normal cardiac output. The purpose of this project is to evaluate the effectiveness of a new manual CPR device that provides sequential thoracic and sternal (cardiac) compression. The specific aims of the project include defining the mechanism of blood flow produced by the device, measuring intravascular pressures, blood flow, and ventilation during prolonged CPR with the device, and evaluating short-term outcome when the device is compared to standard manual CPR. All studies will be undertaken in the research laboratory and design modifications of the device will be made based upon laboratory observations. The mechanism of blood flow will be assessed with pressure synchronized cine-angiography, transesophageal 2-D Doppler echocardiography, and high-fidelity hemodynamic measurements. Cardiac output, coronary perfusion pressure, and ventilation produced by the device will be evaluated in an animal model of VF cardiac arrest and resuscitation. The new CPR device will be compared to conventional manual CPR with a study end-point of short-term outcome and survival for three hours. The long-term objective of the project is the production of a simple manual CPR device that will produce greater blood flow than standard CPR, negate the need for mouth-to-mouth ventilation, and that can be used by the lay person with minimal instruction. The device could easily be deployed with existing automatic external defibrillators (AEDs), which provide brief and simple audio instruction regarding use. Use of early and effective CPR with the new device preceding or following early defibrillation attempts by lay persons (public access defibrillation) could result in more lives saved. [unreadable] [unreadable]